source: trunk/VUT/GtpVisibilityPreprocessor/src/X3dExporter.cpp @ 380

#include <stack>
#include "common.h"
#include "SceneGraph.h"
#include "X3dExporter.h"
#include "Mesh.h"
#include "KdTree.h"
#include "ViewCellBsp.h"
#include "ViewCell.h"
#include "Polygon3.h"

X3dExporter::X3dExporter(const string filename):Exporter(filename)
{
  stream.open(mFilename.c_str());
  stream<<"<?xml version=\"1.0\" encoding=\"UTF-8\"?>"<<endl;
  stream<<"<X3D>"<<endl;
  stream<<"<Scene>"<<endl;
  
}

X3dExporter::~X3dExporter()
{
  stream<<"</Scene>"<<endl;
  stream<<"</X3D>"<<endl;
  stream.close();
}


bool
X3dExporter::ExportRays(const vector<Ray> &rays,
                        const float length,
                        const RgbColor &color)
{
  vector<Ray>::const_iterator ri = rays.begin();
  stream<<"<Shape>"<<endl;
  stream<<"<Appearance>"<<endl;
  stream<<"<Material ambientColor=\""<<color.r<<" "<<color.g<<" "<<color.b<<
    "\" />"<<endl;
  stream<<"</Appearance>"<<endl;
  
  stream<<"<IndexedLineSet coordIndex=\""<<endl;

  int index = 0;
  for (; ri != rays.end(); ri++) {
    stream<<index<<" "<<index+1<<" -1\n";
    index+=2;
  }
  
  stream<<"\" >"<<endl;
  
  stream<<"<Coordinate  point=\""<<endl;
  
  ri = rays.begin();
  for (; ri != rays.end(); ri++) {
    Vector3 a = (*ri).GetLoc();
    
    Vector3 b;
    if (length < 0)
      b = (*ri).GetLoc() - length*(*ri).GetDir();
    else
      if ((*ri).intersections.size()==0)
        b = (*ri).GetLoc() + length*(*ri).GetDir();
      else
        b = (*ri).Extrap((*ri).intersections[0].mT);
    
    stream<<a.x<<" "<<a.y<<" "<<a.z<<" ,";
    stream<<b.x<<" "<<b.y<<" "<<b.z<<" ,\n";
  }
  
  stream<<"\" >"<<endl;
  stream<<"</Coordinate>"<<endl;
  stream<<"</IndexedLineSet>"<<endl;
  stream<<"</Shape>"<<endl;
  return true;
}

bool
X3dExporter::ExportRays(const RayContainer &rays,
                                                const float length,
                                                const RgbColor &color)
{
  RayContainer::const_iterator ri = rays.begin();

  stream<<"<Shape>"<<endl;
  stream<<"<Appearance>"<<endl;
  stream<<"<Material ambientColor=\""<<color.r<<" "<<color.g<<" "<<color.b<<
    "\" />"<<endl;
  stream<<"</Appearance>"<<endl;
  
  stream<<"<IndexedLineSet coordIndex=\""<<endl;

  int index = 0;
  for (; ri != rays.end(); ri++) {
    stream<<index<<" "<<index+1<<" -1\n";
    index+=2;
  }
  
  stream<<"\" >"<<endl;
  
  stream<<"<Coordinate  point=\""<<endl;
  
  ri = rays.begin();
  for (; ri != rays.end(); ri++) {
    Vector3 a = (*ri)->GetLoc();
    
    Vector3 b;
    if (length < 0)
      b = (*ri)->GetLoc() - length*(*ri)->GetDir();
    else
      if ((*ri)->intersections.size()==0)
        b = (*ri)->GetLoc() + length*(*ri)->GetDir();
      else
        b = (*ri)->Extrap((*ri)->intersections[0].mT);
    
    stream<<a.x<<" "<<a.y<<" "<<a.z<<" ,";
    stream<<b.x<<" "<<b.y<<" "<<b.z<<" ,\n";
  }
  
  stream<<"\" >"<<endl;
  stream<<"</Coordinate>"<<endl;
  stream<<"</IndexedLineSet>"<<endl;
  stream<<"</Shape>"<<endl;

  return true;
}

void
X3dExporter::ExportSceneNode(SceneGraphNode *node)
{
  stream<<"<Group>"<<endl;

  SceneGraphNodeContainer::iterator ni = node->mChildren.begin();
  for (; ni != node->mChildren.end(); ni++)
    ExportSceneNode(*ni);
  
  
  ObjectContainer::const_iterator mi = node->mGeometry.begin();
  for (; mi != node->mGeometry.end(); mi++) {
    // export the transform...
    ExportIntersectable(*mi);
  }
  
  stream<<"</Group>"<<endl;

}
void
X3dExporter::ExportIntersectable(Intersectable *object)
{
  switch (object->Type()) {
  case Intersectable::MESH_INSTANCE:
  case Intersectable::TRANSFORMED_MESH_INSTANCE:
    ExportMeshInstance((MeshInstance *)object);
        break;
  case Intersectable::VIEW_CELL:
        ExportViewCell((ViewCell *)object);
    break;
  default:
    cerr<<"Sorry the export for object not yet defined"<<endl;
    break;
  }
}

void
X3dExporter::ExportMeshInstance(MeshInstance *object)
{
  // $$JB$$
  // in the future check whether the mesh was not already exported
  // and use a reference to the that mesh instead
  ExportMesh(object->GetMesh());
}

void 
X3dExporter::ExportViewCells(const ViewCellContainer &viewCells)
{
        ViewCellContainer::const_iterator it, it_end = viewCells.end();

        for (it = viewCells.begin(); it != it_end; ++ it)
                ExportViewCell(*it);
}

void 
X3dExporter::ExportBspViewCellPartition(const BspTree &tree, const int maxPvs)
{
        ViewCellContainer viewCells;
        tree.CollectViewCells(viewCells);

        ViewCellContainer::const_iterator it, it_end = viewCells.end();


        if (maxPvs > 0)
                mUseForcedMaterial = true;

        for (it = viewCells.begin(); it != it_end; ++ it)
        {
                if (maxPvs > 0)
                {
                        mForcedMaterial.mDiffuseColor.b = 1.0f;
                        float importance = (float)(*it)->GetPvs().GetSize() / (float)maxPvs;

                        mForcedMaterial.mDiffuseColor.r = importance;
                        mForcedMaterial.mDiffuseColor.g = 1.0f - mForcedMaterial.mDiffuseColor.r;
                }

                if ((*it)->GetMesh())
                        ExportViewCell(*it);
                else
                {
                        PolygonContainer cell;
                        tree.ConstructGeometry(dynamic_cast<BspViewCell *>(*it), cell);

                        ExportPolygons(cell);
                }
        }
}

void 
X3dExporter::ExportBspLeaves(const BspTree &tree)
{
        vector<BspLeaf *> leaves;
        tree.CollectLeaves(leaves);

        vector<BspLeaf *>::const_iterator it, it_end = leaves.end();

        for (it = leaves.begin(); it != it_end; ++ it)
        {
                PolygonContainer cell;
                tree.ConstructGeometry(*it, cell);
                ExportPolygons(cell);
        }
}

void
X3dExporter::ExportViewCell(ViewCell *viewCell)
{
        if (viewCell->GetMesh())
                ExportMesh(viewCell->GetMesh());
}

void
X3dExporter::ExportMesh(Mesh *mesh)
{

  stream<<"<Shape>"<<endl;
  stream<<"<Appearance>"<<endl;
  
  // $$ tmp -> random material
  
  float r, g, b;

  if (mUseForcedMaterial) {
    r = mForcedMaterial.mDiffuseColor.r;
    g = mForcedMaterial.mDiffuseColor.g;
    b = mForcedMaterial.mDiffuseColor.b;
    
  } else
    if (mesh->mMaterial) {
      r = mesh->mMaterial->mDiffuseColor.r;
      g = mesh->mMaterial->mDiffuseColor.g;
      b = mesh->mMaterial->mDiffuseColor.b;
    } else {
      r = RandomValue(0.5, 1.0);
      g = RandomValue(0.5, 1.0);
      b = RandomValue(0.5, 1.0);
    }
  stream<<"<Material diffuseColor=\""<<r<<" "<<g<<" "<<b<<
    "\" specularColor=\"0.0 0.0 0.0\"/>"<<endl;
  stream<<"</Appearance>"<<endl;


  if (mWireframe)
    stream<<"<IndexedLineSet ccw=\"TRUE\" coordIndex=\""<<endl;
  else
    stream<<"<IndexedFaceSet ccw=\"TRUE\" coordIndex=\""<<endl;

  FaceContainer::const_iterator fi = mesh->mFaces.begin();

  int index = 0;
  
  for (; fi != mesh->mFaces.end(); fi++) {
    Face *face = *fi;
    VertexIndexContainer::const_iterator vi = face->mVertexIndices.begin();
    for (; vi != face->mVertexIndices.end(); vi++)
      stream<<*vi<<" ";
        if (mWireframe) // final line to finish polygon
                stream << (*face->mVertexIndices.begin()) << " ";

    stream<<"-1"<<endl;
  }
  stream<<"\" >"<<endl;

  stream<<"<Coordinate  point=\""<<endl;
  
  VertexContainer::const_iterator vi = mesh->mVertices.begin();
  for (; vi != mesh->mVertices.end(); vi++) {
    stream<<(*vi).x<<" "<<(*vi).y<<" "<<(*vi).z;
    stream<<","<<endl;
  }
  
  stream<<"\" >"<<endl;
  stream<<"</Coordinate>"<<endl;

  if (mWireframe)
    stream<<"</IndexedLineSet>"<<endl;
  else
    stream<<"</IndexedFaceSet>"<<endl;
  
  stream<<"</Shape>"<<endl;

}


void X3dExporter::ExportPolygon(Polygon3 *poly)
{
        stream << "<Shape>" << endl;
        stream << "<Appearance>" << endl;
  
        // $$ tmp -> random material
  
        float r, g, b;

        if (mUseForcedMaterial) 
        {
                r = mForcedMaterial.mDiffuseColor.r;
                g = mForcedMaterial.mDiffuseColor.g;
                b = mForcedMaterial.mDiffuseColor.b;
        } 
        else if (poly->mMaterial) 
        {
                r = poly->mMaterial->mDiffuseColor.r;
                g = poly->mMaterial->mDiffuseColor.g;
                b = poly->mMaterial->mDiffuseColor.b;
        } else 
        {
                r = RandomValue(0.5, 1.0);
                g = RandomValue(0.5, 1.0);
                b = RandomValue(0.5, 1.0);
        }

        stream << "<Material diffuseColor=\"" << r << " " << g << " " << b 
                   << "\" specularColor=\"0.0 0.0 0.0\"/>" << endl;

    stream << "</Appearance>" << endl;


        //-- create and write indices
        if (mWireframe)
                stream << "<IndexedLineSet ccw=\"TRUE\" coordIndex=\"" << endl;
        else
                stream << "<IndexedFaceSet ccw=\"TRUE\" coordIndex=\"" << endl;

        int index = 0;
        
        VertexContainer::const_iterator vi;  
        
        for (index = 0; index < (int)poly->mVertices.size(); ++ index) 
                stream << index << " ";
        
        if (mWireframe) // final line to finish polygon
                stream << "0 ";

        stream << "-1" << endl;
        stream << "\" >" << endl;
        
        stream << "<Coordinate  point=\"" << endl;
  
        for (vi = poly->mVertices.begin(); vi != poly->mVertices.end(); ++vi) 
        {
                stream << (*vi).x << " " << (*vi).y << " " << (*vi).z;
                stream << "," << endl;
        }
  
        stream << "\" >" << endl;
        stream << "</Coordinate>" << endl;

        if (mWireframe)
                stream << "</IndexedLineSet>" << endl;
        else
                stream << "</IndexedFaceSet>" << endl;
  
        stream << "</Shape>" << endl;
}

void X3dExporter::ExportPolygons(const PolygonContainer &polys)
{
        stream << "<Shape>" << endl;
        stream << "<Appearance>" << endl;
  
        // $$ tmp -> random material
  
        float r, g, b;

        if (mUseForcedMaterial) 
        {
                r = mForcedMaterial.mDiffuseColor.r;
                g = mForcedMaterial.mDiffuseColor.g;
                b = mForcedMaterial.mDiffuseColor.b;
        } 
        else 
        {
                r = RandomValue(0.5, 1.0);
                g = RandomValue(0.5, 1.0);
                b = RandomValue(0.5, 1.0);
        }

        stream << "<Material diffuseColor=\"" << r << " " << g << " " << b 
                   << "\" specularColor=\"0.0 0.0 0.0\"/>" << endl;

    stream << "</Appearance>" << endl;


        //-- create and write indices
        if (mWireframe)
                stream << "<IndexedLineSet ccw=\"TRUE\" coordIndex=\"" << endl;
        else
                stream << "<IndexedFaceSet ccw=\"TRUE\" coordIndex=\"" << endl;

        int index = 0;
        
        PolygonContainer::const_iterator pit;

    VertexContainer::const_iterator vi;  
        
        for (pit = polys.begin(); pit != polys.end(); ++pit)
        {
                Polygon3 *poly = *pit;
                int startIdx = index;
                for (vi = poly->mVertices.begin(); vi != poly->mVertices.end(); ++vi) 
                {
                        stream << index ++ << " ";
                }

                stream << startIdx << " ";// finish line
                stream << "-1" << endl;
        }

        stream << "\" >" << endl;
        
        stream << "<Coordinate  point=\"" << endl;
        for (pit = polys.begin(); pit != polys.end(); ++ pit)
        {
                Polygon3 *poly = *pit;
        for (vi = poly->mVertices.begin(); vi != poly->mVertices.end(); ++vi) 
                {
                        stream << (*vi).x << " " << (*vi).y << " " << (*vi).z;
                        stream << "," << endl;
                }
        }
        stream << "\" >" << endl;
        stream << "</Coordinate>" << endl;

        if (mWireframe)
                stream << "</IndexedLineSet>" << endl;
        else
                stream << "</IndexedFaceSet>" << endl;
  
        stream << "</Shape>" << endl;
}

bool
X3dExporter::ExportBox(const AxisAlignedBox3 &box)
{
  Mesh *mesh = new Mesh;
  // add 6 vertices of the box
  int index = (int)mesh->mVertices.size();
  for (int i=0; i < 8; i++) {
    Vector3 v;
    box.GetVertex(i, v);
    mesh->mVertices.push_back(v);
  }
  
  mesh->AddFace(new Face(index + 0, index + 1, index + 3, index + 2) );
  mesh->AddFace(new Face(index + 0, index + 2, index + 6, index + 4) );
  mesh->AddFace(new Face(index + 4, index + 6, index + 7, index + 5) );
  
  mesh->AddFace(new Face(index + 3, index + 1, index + 5, index + 7) );
  mesh->AddFace(new Face(index + 0, index + 4, index + 5, index + 1) );
  mesh->AddFace(new Face(index + 2, index + 3, index + 7, index + 6) );
  
  ExportMesh(mesh);
  delete mesh;
  return true;
}

bool
X3dExporter::ExportBspTree(const BspTree &tree)
{
        if (mExportRayDensity) 
        {
                return ExportBspTreeRayDensity(tree);
        }
  
        stack<BspNode *> tStack;

        tStack.push(tree.GetRoot());

        Mesh *mesh = new Mesh;

        AxisAlignedBox3 box = tree.GetBoundingBox();
        bool savedWireframe = mWireframe;

        SetWireframe();
        ExportBox(box);
        
        if (!savedWireframe)
                SetFilled();

        //ViewCellContainer foundViewCells;

        if (BspTree::sStoreSplitPolys)
        {
                while (!tStack.empty()) 
                {
            BspNode *node = tStack.top();
    
                        tStack.pop();
        
                        PolygonContainer::const_iterator it;
                        PolygonContainer::const_iterator it_end = node->GetPolygons()->end();

                        for (it = node->GetPolygons()->begin(); it != it_end; ++ it)
                                ExportPolygon(*it);
                        
                        if (!node->IsLeaf()) 
                        {
                                BspInterior *interior = dynamic_cast<BspInterior *>(node);
      
                                tStack.push(interior->GetFront());
                                tStack.push(interior->GetBack());

                        }
                }
        }
        // export view cells
        ExportBspViewCellPartition(tree);       

        return true;
}

bool X3dExporter::ExportKdTree(const KdTree &tree)
{
         if (mExportRayDensity) {
    return ExportKdTreeRayDensity(tree);
  }
  
  stack<KdNode *> tStack;

  tStack.push(tree.GetRoot());

  Mesh *mesh = new Mesh;
  
  while (!tStack.empty()) {
    KdNode *node = tStack.top();
    tStack.pop();
    AxisAlignedBox3 box = tree.GetBox(node);
    // add 6 vertices of the box
    int index = (int)mesh->mVertices.size();
    for (int i=0; i < 8; i++) {
      Vector3 v;
      box.GetVertex(i, v);
      mesh->mVertices.push_back(v);
    }
    mesh->AddFace(new Face(index + 0, index + 1, index + 3, index + 2) );
    mesh->AddFace(new Face(index + 0, index + 2, index + 6, index + 4) );
    mesh->AddFace(new Face(index + 4, index + 6, index + 7, index + 5) );

    mesh->AddFace(new Face(index + 3, index + 1, index + 5, index + 7) );
    mesh->AddFace(new Face(index + 0, index + 4, index + 5, index + 1) );
    mesh->AddFace(new Face(index + 2, index + 3, index + 7, index + 6) );

    if (!node->IsLeaf()) {
      KdInterior *interior = (KdInterior *)node;
      tStack.push(interior->mFront);
      tStack.push(interior->mBack);
    }
  }
  
  ExportMesh(mesh);
  delete mesh;
  return true;
        // TODO
        return true;
}


bool
X3dExporter::ExportBspTreeRayDensity(const BspTree &tree)
{
        stack<BspNode *> tStack;

        tStack.push(tree.GetRoot());

        bool fm = mUseForcedMaterial;
        
        mUseForcedMaterial = true;
        
        mForcedMaterial.mDiffuseColor.g = 1.0f;
        mForcedMaterial.mDiffuseColor.b = 1.0f;
  
        while (!tStack.empty()) 
        {
                BspNode *node = tStack.top();
                tStack.pop();

                if (node->IsLeaf()) 
                {
                        ViewCell *vc = dynamic_cast<BspLeaf *>(node)->GetViewCell();
     
                        // set the mesh material according to the ray density
                        if (vc->mPassingRays.mRays) 
                        {
                                float importance = 
                                        vc->mPassingRays.mContributions / (float)vc->mPassingRays.mRays;

                                mForcedMaterial.mDiffuseColor.r = importance;
                                mForcedMaterial.mDiffuseColor.g = 1.0f - mForcedMaterial.mDiffuseColor.r;
                                ExportViewCell(vc);
                        }  
                } else 
                {
                        BspInterior *interior = (BspInterior *)node;
                        tStack.push(interior->GetFront());
                        tStack.push(interior->GetBack());
                }
        }
  
        // restore the state of forced material
        mUseForcedMaterial = fm;

        return true;
}

bool
X3dExporter::ExportKdTreeRayDensity(const KdTree &tree)
{
  stack<KdNode *> tStack;

  tStack.push(tree.GetRoot());

  bool fm = mUseForcedMaterial;
  mUseForcedMaterial = true;
  mForcedMaterial.mDiffuseColor.g = 1.0f;
  mForcedMaterial.mDiffuseColor.b = 1.0f;
  while (!tStack.empty()) {
    KdNode *node = tStack.top();
    tStack.pop();
    if (node->IsLeaf()) {
      AxisAlignedBox3 box = tree.GetBox(node);
      Mesh *mesh = new Mesh;
      
      // add 6 vertices of the box
      int index = (int)mesh->mVertices.size();
      for (int i=0; i < 8; i++) {
        Vector3 v;
        box.GetVertex(i, v);
        mesh->mVertices.push_back(v);
      }
      mesh->AddFace(new Face(index + 0, index + 1, index + 3, index + 2) );
      mesh->AddFace(new Face(index + 0, index + 2, index + 6, index + 4) );
      mesh->AddFace(new Face(index + 4, index + 6, index + 7, index + 5) );
      
      mesh->AddFace(new Face(index + 3, index + 1, index + 5, index + 7) );
      mesh->AddFace(new Face(index + 0, index + 4, index + 5, index + 1) );
      mesh->AddFace(new Face(index + 2, index + 3, index + 7, index + 6) );


      // set the mesh material according to the ray density
      KdLeaf *leaf = (KdLeaf *) node;
      if (leaf->mPassingRays.mRays) {
        float importance = leaf->mPassingRays.mContributions/(float)leaf->mPassingRays.mRays;
        //      float importance = leaf->mPassingRays.mContributions/1000.0f;
        //      float importance = leaf->mPassingRays.mRays/1000.0f;
        ///(float)leaf->mPassingRays.mRays;
        // mForcedMaterial.mDiffuseColor.r = log10(leaf->mPassingRays.mRays)/3.0f;
        mForcedMaterial.mDiffuseColor.r = importance;
        mForcedMaterial.mDiffuseColor.g = 1.0f - mForcedMaterial.mDiffuseColor.r;
        ExportMesh(mesh);
      }
      delete mesh;
    } else {
      KdInterior *interior = (KdInterior *)node;
      tStack.push(interior->mFront);
      tStack.push(interior->mBack);
    }
  }
  // restore the state of forced material
  mUseForcedMaterial = fm;
  return true;
}


struct BspSplitData
{
        /// the current node
        BspNode *mNode;

        vector<Plane3 *> mPlanes;
        vector<bool> mSides;
        bool mIsFront;

        BspSplitData(BspNode *node): 
        mNode(node), mIsFront(false)
        {};     
        BspSplitData(BspNode *node, 
                                vector<Plane3 *> planes, 
                                vector<bool> sides, 
                                bool isFront): 
        mNode(node), mPlanes(planes), 
        mSides(sides), mIsFront(isFront)
        {};
};

void X3dExporter::ExportLeavesGeometry(const BspTree &tree, const vector<BspLeaf *> &leaves)
{
        vector<BspLeaf *>::const_iterator it, it_end = leaves.end();

        for (it = leaves.begin(); it != it_end; ++ it)
        {
                PolygonContainer cell;
                tree.ConstructGeometry(*it, cell);
                
                ExportPolygons(cell);

                CLEAR_CONTAINER(cell);
        }
}

void X3dExporter::ExportBspSplits(const BspTree &tree)
{
        std::stack<BspSplitData> tStack;

        BspSplitData tData(tree.GetRoot());
        tStack.push(tData);
  
        PolygonContainer polys;

        while (!tStack.empty())
        {
                // filter polygons donw the tree
                BspSplitData tData = tStack.top();
            tStack.pop();       
                
                if (!tData.mNode->IsLeaf())
                {
                        BspInterior *interior = dynamic_cast<BspInterior *>(tData.mNode);

                        if (tData.mNode != tree.GetRoot())
                                tData.mSides.push_back(tData.mIsFront); // add current side of split plane

                        // bounded plane is added to the polygons
                        Polygon3 *planePoly = tree.GetBoundingBox().CrossSection(*interior->GetPlane());
                
                        // do all the splits with the previous planes
                        for (int i = 0; i < (int)tData.mPlanes.size(); ++ i)
                        {
                                VertexContainer splitPts;
                                
                                if (planePoly->ClassifyPlane(*tData.mPlanes[i]) == Polygon3::SPLIT)
                                {
                                        Polygon3 *frontPoly = new Polygon3();
                                        Polygon3 *backPoly = new Polygon3();

                                        planePoly->Split(*tData.mPlanes[i], *frontPoly, *backPoly, splitPts);
                                        DEL_PTR(planePoly);

                                        if(tData.mSides[i] == true)
                                        {
                                                planePoly = frontPoly;
                                                DEL_PTR(backPoly);
                                        }
                                        else
                                        {
                                                planePoly = backPoly;
                                                DEL_PTR(frontPoly);
                                        }
                                }
                        }

                        tData.mPlanes.push_back(interior->GetPlane()); // add plane to split planes

                        if (planePoly->Valid())
                                polys.push_back(planePoly);
                        else
                                DEL_PTR(planePoly);
                        
                        // push the children on the stack
                        tStack.push(BspSplitData(interior->GetFront(), tData.mPlanes, tData.mSides, true));
                        tStack.push(BspSplitData(interior->GetBack(), tData.mPlanes, tData.mSides, false));
                }
        }       
        ExportPolygons(polys);
        CLEAR_CONTAINER(polys);
}

void X3dExporter::ExportBspSplitPlanes(const BspTree &tree)
{
        std::stack<BspNode *> tStack;

        tStack.push(tree.GetRoot());
  
        PolygonContainer polys;

        while (!tStack.empty())
        {
                // filter polygons donw the tree
                BspNode *node = tStack.top();
            tStack.pop();       
                
                if (!node->IsLeaf())
                {
                        BspInterior *interior = dynamic_cast<BspInterior *>(node);

                        // bounded plane is added to the polygons
                        polys.push_back(tree.GetBoundingBox().CrossSection(*interior->GetPlane()));
                
                        // push the children on the stack
                        tStack.push(interior->GetBack());
                        tStack.push(interior->GetFront());
                }
        }

        ExportPolygons(polys);
        CLEAR_CONTAINER(polys);
}